Captive Hamilton’s frog (Leiopelma hamiltoni) associates non-randomly under retreat sites: preliminary insights into their social networks

Abstract

Hamilton’s frog (Leiopelma hamiltoni) is often found co-habiting retreat sites in the wild and in captivity, but whether co-habitation is a facet of sociality remains to be explored. We investigated the association patterns of retreat site sharing in four captive colonies of L. hamiltoni using a social networking framework. We tested whether the strength and heterogeneity of associations between individuals of each network varied from expected, or if frogs shared retreat sites randomly. We also investigated the temporal stability of pair-wise associations. In all tanks, we found that frogs shared retreat sites significantly more than would be expected if they displayed no degree of association. Further, we observed more preferred and avoided pairings than would be expected at random. Temporal stability between pairs of individuals within a tank were stable over short time periods (10–50 days) but decreased over time. High variation within and between tanks, however, prevented us from establishing a clear trend in temporal stability. Our results suggest that captive L. hamiltoni frogs, at least over the short-term, preferentially select retreat sites with specific individuals, and from this we infer that sociality in the form of retreat site sharing may form a key component of L. hamiltoni biology.